Apparatus, arrangement and method for the production of an aerosol of charged nanoparticles

Abstract

An apparatus to produce an aerosol of charged nanoparticles includes a charging device and an electrically conductive tube. The charging device includes an inlet for nanoparticles and an outlet. The charging device is configured to charge the nanoparticles. The electrically conductive tube includes an input port and an output port. The input port is arranged at the outlet of the charging device. A length l of the tube is at least 2.5 times a cross-sectional inner diagonal d of the tube.

1 . An apparatus for the production of an aerosol of charged nanoparticles, the apparatus comprising:
 a charging device comprising an inlet for nanoparticles and an outlet, the charging device being configured to charge the nanoparticles; and   an electrically conductive tube comprising an input port and an output port, the input port being arranged at the outlet of the charging device, a length l of the tube being at least 2.5 times a cross-sectional inner diagonal d of the tube.   
     
     
         2 . The apparatus according to  claim 1 , wherein the tube comprises a uniform cross-section. 
     
     
         3 . The apparatus according to  claim 1 , wherein the tube comprises a circular cross-section, or wherein the tube comprises a poly-angular, in particular rectangular, cross-section. 
     
     
         4 . The apparatus according to  claim 1 , wherein the charging device is configured to positively or negatively charge the nanoparticles with at least 0.5 charge states per nanoparticle on average. 
     
     
         5 . The apparatus according to  claim 1 , wherein a wall of the tube is configured to serve as an electrode, which is held at an electrical potential. 
     
     
         6 . The apparatus according to  claim 1 , wherein the length l of the tube is at least 15 times the cross-sectional inner diagonal d of the tube, or wherein the length l of the tube is at least 20 times the cross-sectional inner diagonal d of the tube. 
     
     
         7 . The apparatus according to  claim 1 , wherein the apparatus is configured to by operated in a regime where V S /B>60, wherein V S  is the non-dimensional charged nanoparticle mobility and β is defined as β=2·l/d·P em , with P em  being the mass Péclet number. 
     
     
         8 . An arrangement for the production of an aerosol of charged nanoparticles, comprising:
 an apparatus including:
 a charging device comprising an inlet for nanoparticles and an outlet, the charging device being configured to charge the nanoparticles, and 
 an electrically conductive tube comprising an input port and an output port, the input port being arranged at the outlet of the charging device, a length l of the tube being at least 2.5 times a cross-sectional inner diagonal d of the tube; and 
   a particle generator arranged at the inlet of the charging device, the particle generator being configured to generate nanoparticles for passing them to the inlet of the charging device.   
     
     
         9 . The arrangement according to  claim 8 , further comprising:
 a particle counting device arranged at the output port of the tube, the particle counting device configured to count the nanoparticles at the output port.   
     
     
         10 . The arrangement according to  claim 8 , wherein the tube comprises a uniform cross-section. 
     
     
         11 . The arrangement according to  claim 8 , wherein the charging device is configured to positively or negatively charge the nanoparticles with at least 0.5 charge states per nanoparticle on average. 
     
     
         12 . The arrangement according to  claim 8 , wherein a wall of the tube is configured to serve as an electrode, which is held at an electrical potential. 
     
     
         13 . The arrangement according to  claim 8 , wherein the length  1  of the tube is at least 15 times the cross-sectional inner diagonal d of the tube, or wherein the length l of the tube is at least 20 times the cross-sectional inner diagonal d of the tube. 
     
     
         14 . The arrangement according to  claim 8 , wherein the apparatus is configured to by operated in a regime where V S /β>60, wherein V S  is the non-dimensional charged nanoparticle mobility and β is defined as β=2·l/d·P em , with P em  being the mass Peclet number. 
     
     
         15 . A method for producing an aerosol of charged nanoparticles, the method comprising:
 providing a charging device comprising an inlet for nanoparticles and an outlet;   providing an electrically conductive tube comprising an input port and an output port, a length l of the tube being at least 2.5 times a cross-sectional inner diagonal d of the tube;   arranging the input port of the tube at the outlet of the charging device;   charging nanoparticles by means of the charging device; and   passing the charged nanoparticles through the outlet to the output port of the tube.   
     
     
         16 . The method according to  claim 15 , further comprising:
 selecting an aspect ratio of the tube based on a predetermined output number concentration of charged nanoparticles at the output port of the tube.   
     
     
         17 . The method according to  claim 15 , further comprising:
 generating nanoparticles via a particle generator; and   passing the nanoparticles to the inlet of the charging device.   
     
     
         18 . The method according to  claim 17 , wherein the particle generator generates nanoparticles at a number concentration of at least 10 4  particles per cm 3  at a flowrate of at least 100 milliliters per minute and at most 30 liters per minute. 
     
     
         19 . The method according to  claim 17 , wherein the particle generator generates nanoparticles with mobility diameters of at least 3 nm and at most 1000 nm, or mobility diameters of at least 15 nm and at most 75 nm. 
     
     
         20 . The method according to  claim 17 , wherein the particle generator generates nanoparticles at a number concentration of at least 20/P D  times and at most 1000 times a predetermined number concentration of charged nanoparticles at the output port of the tube, wherein P D  is the diffusion based particle penetration.